IRRITABLE BOWEL SYNDROME

Irritable bowel syndrome (IBS) or spastic colon affects 5-20 percent population. It is likely that you or someone you know has irritable bowel syndrome. But what is this irritable bowel syndrome or spastic colon or IBS?

IBS is a symptom based diagnosis of unclear etiology. It should not be confused with diverticulosis or diverticultis. Irritable bowel syndrome is probably is not a single disease. More likely, IBS is comprised of multiple diseases, all lumped into one at the present time for lack of understanding its pathogenesis. Infantile colic is considered by many to be a variant of IBS in infants and kids.

Features of irritable bowel syndrome and Rome criteria

Irritable bowel syndrome is a functional disorder characterized by chronic (at least three months in the preceding one year) abdominal pain and a disturbance of bowel habit. The disturbed bowel habit of IBS may manifest as diarrhea, constipation or alternating diarrhea with constipation. Pain frequently improves with defecation.

A waxing and waning pattern of symptoms is seen in most patients. The precise conglomeration of symptom complex is defined under ROME III criteria.

My opinion: IBS occurs when there is a perfect storm of combination of increased intestinal permeability (Leaky gut) and low grade inetestinal inflammation, altered gut bacteria and some harmful factor in gut lumen in a patient with genetic predisposition. The role of diet in at least affecting the IBS manifestations can not be emphasized enough.

Note: The leaky gut, inflammation and altered bacteria can affect not only the gut but also systems far away including the brain.

IBS medical consensus

Overall, in the absence of clear cut cause, a bio-psychosocial model for pathogenesis for irritable bowel syndrome has been proposed. This model emphasizes the role of mind-body interactions with the environment.

In this context, it should be noted that there is an increased prevelance of certain chronic pain disorders in IBS patients, e.g. functional dyspepsia, fibromyalgia, chronic fatigue syndrome, interstitial cystitis, chronic back pain etc.

While the diagnosis of irritable bowel syndrome should be positive, physicians frequently perform studies to exclude any treatable cause. The work up for IBS should be individualized and may include complete blood count (CBC), routine chemistries and stool studies. Flexible sigmoidoscopy or colonoscopy may be performed depending upon age and risk for colon cancer and suspicion for alternative diagnosis like inflammatory bowel disease (Crohn's disease and ulcerative colitis).

Celiac sprue should be excluded by antibody testing for anti-tissue transglutaminase antibody. The use of anti-gliadin antibody has recently seen a resurgence with the identification that many IBS patients get relief from gluten free diet.

Lactose hydrogen breath test may be done to exclude lactose intolerance. Small bowel bacterial overgrowth can be excluded by hydrogen breath test or cultures of small bowel aspirate.

The management of IBS patients follows a step-wise fashion and is largely symptom based. Realistic goals need to be established. Reassurance with a lot of hand-holding goes a long way in helping patient cope with the symptoms of IBS.

Placebo response rate in irritable bowel syndrome may be as high as fifty percent.

Role of Diet: An often an forgotten factor in management

High fiber diet and fluid are frequently prescribed as first line of treatment for IBS of all types. Much of positive data about fiber in IBS pertains to Isubghulla type.

Patients with diarrhea may be helped by lactose-avoidance.

Patients can frequently identify provoking factors and need to abstain

Over the counter laxatives or prescription medication Zelnorm are used in cases with constipation predominant IBS. Of note, Zelnorm was withdrawn from US market on March 30, 2007 because of unacceptable side-effects. Lubiprostone and Linzess are available.

Constipating agents like Imodium and Lomotil may be needed in patients with diarrhea predominant IBS. Lotronex is useful for diarrhea-predominant IBS but has high risk for ischemic colitis. Its availability is limited and its use in IBS has largely been abandoned by most physicians in the US. Its is not to be used for irritable bowel syndrome of constipation type. A recent addition is Viberzi.

Probiotics: Multiple studies have now documented beneficial effects of probiotics in IBS. Note, that all probiotics are not created equal and results depend on the species/strain used.

Treat SIBO if present: Small bowel bacterial overgrowth is treated with antibiotics. Rifaximin, a gut selective antibiotic is frequently used. Probiotics have also been shown to heal small bowel bacterial overgrowth and may have less adverse effects overall as compared to antibiotics.

Role of antidepressents in irritable bowel syndrome

Low dose tricyclic antidepressants (e.g. imipramine, desipramine) raise the pain threshold and are frequently prescribed to IBS patients not responding to above strategies; however their side-effects can be problematic. Although frequently prescribed, there is less data about the use of newer antidepressant agents like SSRIs for management of IBS.

Irritable bowel syndrome (IBS) or spastic colon affects 5-20 percent population. It is likely that you or someone you know has irritable bowel syndrome. But what is this irritable bowel syndrome or spastic colon or IBS?

IBS is a symptom based diagnosis of unclear etiology. It should not be confused with diverticulosis or diverticultis. Irritable bowel syndrome is probably is not a single disease. More likely, IBS is comprised of multiple diseases, all lumped into one at the present time for lack of understanding its pathogenesis. Infantile colic is considered by many to be a variant of IBS in infants and kids.

Features of irritable bowel syndrome and Rome criteria

Irritable bowel syndrome is a functional disorder characterized by chronic (at least three months in the preceding one year) abdominal pain and a disturbance of bowel habit. The disturbed bowel habit of IBS may manifest as diarrhea, constipation or alternating diarrhea with constipation. Pain frequently improves with defecation.

A waxing and waning pattern of symptoms is seen in most patients. The precise conglomeration of symptom complex is defined under ROME III criteria.

My opinion: IBS occurs when there is a perfect storm of combination of increased intestinal permeability (Leaky gut) and low grade inetestinal inflammation, altered gut bacteria and some harmful factor in gut lumen in a patient with genetic predisposition. The role of diet in at least affecting the IBS manifestations can not be emphasized enough.

Note: The leaky gut, inflammation and altered bacteria can affect not only the gut but also systems far away including the brain.

IBS medical consensus

Overall, in the absence of clear cut cause, a bio-psychosocial model for pathogenesis for irritable bowel syndrome has been proposed. This model emphasizes the role of mind-body interactions with the environment.

In this context, it should be noted that there is an increased prevelance of certain chronic pain disorders in IBS patients, e.g. functional dyspepsia, fibromyalgia, chronic fatigue syndrome, interstitial cystitis, chronic back pain etc.

While the diagnosis of irritable bowel syndrome should be positive, physicians frequently perform studies to exclude any treatable cause. The work up for IBS should be individualized and may include complete blood count (CBC), routine chemistries and stool studies. Flexible sigmoidoscopy or colonoscopy may be performed depending upon age and risk for colon cancer and suspicion for alternative diagnosis like inflammatory bowel disease (Crohn's disease and ulcerative colitis).

Celiac sprue should be excluded by antibody testing for anti-tissue transglutaminase antibody. The use of anti-gliadin antibody has recently seen a resurgence with the identification that many IBS patients get relief from gluten free diet.

Lactose hydrogen breath test may be done to exclude lactose intolerance. Small bowel bacterial overgrowth can be excluded by hydrogen breath test or cultures of small bowel aspirate.

The management of IBS patients follows a step-wise fashion and is largely symptom based. Realistic goals need to be established. Reassurance with a lot of hand-holding goes a long way in helping patient cope with the symptoms of IBS.

Placebo response rate in irritable bowel syndrome may be as high as fifty percent.

Role of Diet: An often an forgotten factor in management

High fiber diet and fluid are frequently prescribed as first line of treatment for IBS of all types. Much of positive data about fiber in IBS pertains to Isubghulla type.

Patients with diarrhea may be helped by lactose-avoidance.

Patients can frequently identify provoking factors and need to abstain

Over the counter laxatives or prescription medication Zelnorm are used in cases with constipation predominant IBS. Of note, Zelnorm was withdrawn from US market on March 30, 2007 because of unacceptable side-effects. Lubiprostone and Linzess are available.

Constipating agents like Imodium and Lomotil may be needed in patients with diarrhea predominant IBS. Lotronex is useful for diarrhea-predominant IBS but has high risk for ischemic colitis. Its availability is limited and its use in IBS has largely been abandoned by most physicians in the US. Its is not to be used for irritable bowel syndrome of constipation type. A recent addition is Viberzi.

Probiotics: Multiple studies have now documented beneficial effects of probiotics in IBS. Note, that all probiotics are not created equal and results depend on the species/strain used.

Treat SIBO if present: Small bowel bacterial overgrowth is treated with antibiotics. Rifaximin, a gut selective antibiotic is frequently used. Probiotics have also been shown to heal small bowel bacterial overgrowth and may have less adverse effects overall as compared to antibiotics.

Role of antidepressents in irritable bowel syndrome

Low dose tricyclic antidepressants (e.g. imipramine, desipramine) raise the pain threshold and are frequently prescribed to IBS patients not responding to above strategies; however their side-effects can be problematic. Although frequently prescribed, there is less data about the use of newer antidepressant agents like SSRIs for management of IBS.